Fine Gael leader Enda Kenny called for a Government information campaign for PAYE workers.
He said he knew it was the responsibility of each taxpayer to claim back what he or she was due. However, "many of them may not be aware of their entitlements".
Mr Kenny said research carried out by party finance spokesman Richard Bruton had revealed that in 2003, €185 million had been paid back to 230,000 workers.
"Last year, the figure rose to more than €300 million in respect of 386,000 workers and that is still a long way from tackling the overpayments due. It is estimated that in respect of medical expenses, bin charges and private rents, more than 60 per cent of refunds are not claimed. In these three areas alone, at least €250 million would be paid back to PAYE workers, were those claimed."
Taoiseach Bertie Ahern said targeted campaigns worked. He added that he had no problem, in conjunction with the Department of Finance and the Revenue Commissioners, promoting a campaign to highlight the situation for PAYE people.
"Most years, the Revenue sends out brochures on people's rights along with P60s. There is also a tax charter on individual rights, which it has enhanced in recent years.
"However, I will certainly take up with the Minister for Finance the matter of reliefs such as medical expenses which are not availed of, if that is what the deputy is asking."
Labour leader Pat Rabbitte said the committee stage debate on the Finance Bill had revealed that some 400,000 taxpayers, out of a workforce of two million, had not yet received their tax allowance and credit certificates.
He added that those employed in the Houses of the Oireachtas were told an error had been encountered in the new revenue system, which had resulted in people both underpaying and overpaying tax. The fault was in the Revenue system, not in the Houses of the Oireachtas.
Mr Ahern said he was aware of the late arrival of tax certificates. He was unaware, however, of the underpayment-overpayment of tax by those on the Houses of Oireachtas payroll, and he would ask the Department of Finance to check it.
